The relative motion of such molds (fixed cavity and movable core, fixed core and movable cavity or movable core and movable cavity) occurs along an axis common to both the core and the cavity.
Since, the wall thickness of the articles molded and thus the clearance between core and cavity, in the molding position, ranges from 0.010 to 0.020 inches, it is necessary to maintain accurate alignment of the core and cavity along the common axis to avoid mold damage caused by improper contact between core and cavity during the molding cycle.
A prior art device, over which the present invention is an improvement, is disclosed and described in U.S. Pat. No. 4,556,377, entitled Self-Centering Arrangement for Coacting Forming Tools, issued Dec. 3, 1985 to Paul P. Brown.
The '377 patent discloses an externally tapered mold cavity 15 cooperating with a ring 25 surrounding core 20 having a mating taper as at A to guide the core into the cavity to maintain alignment.
The '377 patent is incorporated into the file of this application.
While the device of the '377 patent is operative, it has not proved satisfactory in situations where the product wall thickness is of the order of 0.010 to 0.020 inches.
In addition, there is no means in the '377 device for effecting a positive "stop" when damaging contact between the core and the mold is imminent.